Communication systems are known to comprise a plurality of base sites that provide communication services to remote units located in corresponding service coverage areas of the base sites. During typical operation, the remote unit moves throughout the coverage area of the serving base site and the serving base site monitors a signal quality metric (e.g., received signal strength indication (RSSI)) of the remote unit's uplink communication signal. To account for changes in RSSI as the remote unit moves, the serving base site will issue commands directing the remote unit to increase or decrease the remote unit's transmit power as the need arises.
Typically, as the remote unit moves to the periphery of the serving base site coverage area, the transmit power of the remote unit as well as the transmit power of the base site must be increased to account for an increase in path losses between the serving base site and the remote unit. In certain situations (e.g., over large bodies of water, or at the frontiers of newly established cellular telephone systems) as the remote unit moves out of the base station's coverage area, there will be insufficient base station power for sustained communication with the remote unit. Additionally, no corresponding base station will be available for handoff purposes. During such instances, the remote unit will be unable to communicate with the communication system. Therefore, a need exists for a method and apparatus for extending coverage in a cellular communication system.